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E. 0. SMITH.

SPEED INDICATOR.

No. 397,395,. Patented Feb. 5, 1889.

Ag 5 fnvezaor; I 24m M UNITED STATES PATENT ()EETCE.

EUGENE C. SMITH, OF ST. LOUIS, MISSOURI, ASBIGXOR OE ONE-HALE TO CLIFTON C. SCIIDDER, OF SAME PLACE.

SPEED=lNDlCATQ-R.

SPECIFICATION forming part of Letters Patent No. 397,395, dated February 5, 1889.

Application filed February 13, 1888. $erial No. 263,856. (No model.)

To all 2071 0m it may concern: A

Be it known that LEUGENE U. Smrn, of the city of St. Louis, in the State of Missouri,

have invented a certain new and useful Improvement in Spee .l.-Indicators, of which the following is a full, clear, and exact descri r tion, referenccbeinhad to the accompanying object to cause the rotation of the index-t wheel.

Figure I is a side view of the instrument. Fig. II is partly in side view and partly in section, showing the instrument in the same form as in Fig. l, and in working position. Fig. III is partly in side view and partly in section, showing the improvement adapted for attachment to an ordinary speed-indicator.

wheel 2 with its scale 3, nor peripheral wormgear teeth l; nor is any novelty claimed in the use of a spindle, 5, carrying a worm, (5, engaging the worm-gear I.

In my improvement, as seen'in Figs. I and II, the spindle 5 has a socket, 7, in an extension, 8, containing a spring, fl, and the head of the center pin 11. At the mouth of the socket is a plate, 12, having a central hole, 13, through which the shank of the center pin passes. The hole is of smaller diameter than the socket, so as to arrest the outward movement of the center pin by the impingement against it of the head 10. At the end of the socket is a cup, ll, to receive the plate 12, and friction pad or disk, 15, which is forced into the cup. The frietionwlisk may be of rubber, leather, or any suitable soft substance which will take good hold of the shaft or other object, 16, against which it is pressed. Rivets or pins 17 are shown to prevent the rotation of the friction-disk 15. The cup may be dispensed with and the rivets depended on to hold the plate 12 and disk 15 in place; or other means maybe employed for this purpose,with this caution that nothing hard shall project beyond the friction-surface 15, nor even be flush with said surface, for it is i11- tended that the friction-surface of the disk shall yield sufficiently to allow a very close contact with the object towhich it is applied.

lVhere the improvement is made for attachment to an ordinary speed-indicator the extension or socket-piece S is formed with a socket, 20, tilted to receive the end 18 of the ordinary worm-spimlle, and the parts are soscured together by a set-screw, 19, or other suitable means.

It will be seen that all the elements of the improvement are contained in the attachment shown in Fig. Ill, its construction being similar to that shown in Fig. II as far as relates to the yielding friction-disk and retreating ccnter pin.

In use of the instrument the end of the center pin, 11, is placed in the center hole of the shaft, or other object whose speed is tobe .tested, but only suliicient pressure is given to keep the pin in this position, so that the worm-spindle does not rotate. The whole at.-

- 7 tention may now be given to the watch and No novelty is claimed in the frame 1, index the instrument pushed forward until the friction-disk 15 bears against the end of the shaft 16, so that the worm-spindle is made to rotate with the same speed as the shaft, there being no slip between the surfaces.

I claim as my invention 1. A speed-imlicator having a rotary porend of said rotary portion adapted for application to the object whose speed is to be determined, said friction -surt'ace being transverse to the axis of rotation of said object, substantially as set forth.

2. A speed-imilicator having a rotary portion, a retreating pin whose point is on the axis of rotation of said rotary portion, and a soft friction-surface at the end of the rotary portion through which the retreating pin passes, substantially as set forth.

3. The combination of the piece S, having a socket, 7, containing a spring and giving bearing to a center pin, against which the outer end of the spring-bears, and a soft: frictionalisk surrounding the center pin, substantially as and for the purpose set forth.

EUGENE C. SMITH. In presence of- SAML. KNIGHT, EDWD. S. KNIGHT.

- tion, and a soft friction-surface at the outer 

